Late blight is a historically famous plant disease that can be very serious in western Washington. It affects potatoes and tomatoes and certain nursery plants and weeds in the Solanaceae (potato family). The disease is capable of causing devastating crop losses, primarily because of the region’s mild, marine climate, which often favors rapid spread. Regardless of the crop or production system—potato or tomato; large or small farms either under conventional or organic management; greenhouses, hoop houses or high tunnels; nurseries or home gardens—late blight can be a problem whenever host plants are present. Successful management in western Washington requires comprehensive cultural and sanitation practices throughout the entire year along with regional cooperation, and, often times, applying protectant fungicides during the growing season
